Locked in a fierce U.S. Senate race, Democrat Al Franken and Republican Norm Coleman together raised more than $7 million in the third quarter of the year, with the challenger pulling in nearly two-thirds of it.

Franken raised more than $4.4 million in the period that ended Sept. 30, and Wednesday reported having $2.8 million to spend in the crucial final weeks of the campaign.

Coleman raised $2.9 million but has more -- nearly $4 million -- left to spend from now until election day.

For the entire election cycle, Coleman has reported raising just over $17.9 million and Franken $15.9 million.

Steven Smith, a professor of political science at Washington University in St. Louis and an expert on Congress, cited several reasons for the big numbers.

"There is a great deal of interest in this because it's a close race, both parties think it's winnable and both parties despise the candidate on the other side," Smith said. "That makes it easy to raise some money within the state and across the country."

Smith also said Franken's fundraising lead in the third quarter can be explained in part by Coleman having plenty of cash in hand for the final weeks and therefore needing to spend less of his time raising money.

Most of Franken's money came in during the last six weeks of the quarter, when both sides ramped up negative television ads that included Coleman spots characterizing Franken as lacking the proper temperament for the office.

Franken received $3 million from Aug. 21 to Sept. 30, nearly twice the contributions brought in by Coleman during that time. The Franken campaign earlier in the election cycle had spent a bigger share of its money, so the late surge in contributions allows it to have a competitive amount of cash on hand.

Coleman spent $3.2 million in just the six weeks prior to Oct. 1 as he and Franken traded a series of tough and expensive ads attacking each other. Franken spent $2.6 million during the same period.

Independence Party candidate Dean Barkley reported raising about $24,000 for the period.

The figures, reported Wednesday to the Federal Election Commission, do not include campaign contributions received or expenses made in the past two weeks. Nor do they reflect spending by independent committees and groups on behalf of the candidates, which have had a prominent role in financing TV ad campaigns.

The Trump administration on Monday banned all use by Americans of Venezuelan cryptocurrency, saying that its introduction is intended to skirt U.S. sanctions. In a separate move, the administration also slapped sanctions on four current and former senior Venezuelan officials accused of corruption and mismanagement.